From f146a31ded2969e90a2a61170aa311add321c9fb Mon Sep 17 00:00:00 2001
From: Sander van Harmelen <svanharmelen@schubergphilis.com>
Date: Thu, 21 May 2015 23:36:54 +0200
Subject: [PATCH] Fixing #2033 by adding a small check on the input
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If the input begins with a shebang, we’ll leave it as is. If not we’ll
add a default shebang…
---
 communicator/ssh/communicator.go | 15 ++++++++++++---
 1 file changed, 12 insertions(+), 3 deletions(-)

diff --git a/communicator/ssh/communicator.go b/communicator/ssh/communicator.go
index 7cf03c870a..402331da11 100644
--- a/communicator/ssh/communicator.go
+++ b/communicator/ssh/communicator.go
@@ -222,10 +222,19 @@ func (c *Communicator) Upload(path string, input io.Reader) error {
 
 // UploadScript implementation of communicator.Communicator interface
 func (c *Communicator) UploadScript(path string, input io.Reader) error {
-	script := bytes.NewBufferString(DefaultShebang)
-	script.ReadFrom(input)
+	reader := bufio.NewReader(input)
+	prefix, err := reader.Peek(2)
+	if err != nil {
+		return fmt.Errorf("Error reading script: %s", err)
+	}
 
-	if err := c.Upload(path, script); err != nil {
+	var script bytes.Buffer
+	if string(prefix) != "#!" {
+		script.WriteString(DefaultShebang)
+	}
+
+	script.ReadFrom(reader)
+	if err := c.Upload(path, &script); err != nil {
 		return err
 	}